Compact liquid dosing apparatus with a reservoir

ABSTRACT

The invention relates to a dosing apparatus with a container having a charging hole for a refill bag with a liquid in the top part, and an outlet in the bottom part. An opening device for the refill bag is fitted above the outlet. A connector leads from the outlet to a downstream pump. A chamber with a level sensor is arranged underneath the reservoir. The reservoir and the chamber are configured so as to be liquid tight, for supplying the liquid without a refill bag. A dosing pump is integrated within the dosing apparatus. A dosing conduit leads from the pump to a point of usage outside the dosing apparatus, and a return conduit leads to the integrated container.

BACKGROUND

1.0 Field of the Invention

The invention relates generally to a metering unit for chemical cleaningagents and cleaning aids, for insuring that such agents and aids aredispensed in a manner to maintain predetermined concentrations for usehandling of substances.

2.0 Discussion of Related Art

In the field of hygiene, various substances are used for cleaning andconditioning the cleaning agents and aids. The substances used are oftenchemical products which are almost always prepared and stored in higherconcentrations than are necessary or appropriate for use. Accordingly,they have to be suitably diluted before or during use. In order to beable to maintain the required concentration of the substances in thesolution during dilution, the substances have to be delivered in theright amount.

In the institutional sector in particular, difficulties are involved inmanually adding the substances in that, this is a labor-intensive taskand, the substances used are often substances which can on contact withhuman skin cause irritation or injury. Because of this, efforts aregenerally made to mechanize and automate the handling of suchsubstances.

If the substances are present in solid or powder form, a dissolvingliquid, for example water, is normally introduced into the storagecontainer so that a certain amount of substance is dissolved and can beput to use. The disadvantage of this procedure is that the concentrationof the substances in the solution is very difficult to control. Anotherdisadvantage of dispensers of this type is that the quantity ofsubstance dispensed varies with varying water pressure and, where thewater pressure is high, is very difficult to determine.

If the substances are present in liquid form, their concentration isgenerally well-defined. Accordingly, liquids can be metered by volume toensure an exact concentration of the liquid in the solution. Meteringsystems of this type are often very complex arrangements which aredifficult to handle. The various units required for carrying out thecorresponding process steps have to be clearly arranged in appropriateassociation and operated accordingly. This calls for considerablealertness and experience on the part of the operator. Accordingly,various attempts have been made to integrate such systems in a neat andcompact form and, at the same time, to guarantee a high degree ofautomation.

WO 95/23549 describes systems in which inter alia the liquid substancesare stored and can be automatically delivered to a following pump. Thedisadvantage of this system is that a refill bag holding the liquidsubstance remains in the unit until it is empty and the pump isexternally arranged. In addition, a very complicated volume controlsystem is required for the pump because excess substance is verydifficult to return where metering is based on volume.

3.0 Summary of the Invention

An object of the present invention is to provide a metering unit thatincludes refill packs that can be removed immediately from a containerof the metering unit after filling it with liquid. Another object is toprovide the metering unit with means for monitoring the level of theliquid concentrate supply in a holding container thereof. Yet anotherobject of the invention is to provide compact packaging for the meteringunit.

In one embodiment of the present invention, with the problems of theprior art in mind, the metering unit includes a chamber with a levelsensor arranged below a storage container, the container and the chamberbeing made liquid-tight to hold the liquid without requiring thepresence of a refill bag, and a metering pump being integrated in themetering unit. A metering line leads to a user outside the meteringunit, and a return line leads back to the integrated container, wherebyone end of each line is connected to the pump.

The present metering unit has the advantage that, because the refill bagdoes not remain in the unit after it is refilled, the unit can be moreeffectively emptied. In addition, possible sources of contamination areeliminated by the removal of the bag after filling because the automaticopening of the bag can lead to uncontrolled damage and leakages ofliquid. Another major advantage is that a metering pump is integratedinto the unit. On the one hand, this enables the returned quantities ofliquid to be directly brought back into the storage container by a shortroute and hence to be re-used. On the other hand, this compactarrangement and, above all, the provision of the level sensor providefor clear and well-organized control and automation.

Since it is impossible to prevent impurities from entering the system,for example through incompetent destruction of the refill bag or throughsoiling thereof, an embodiment in which a fine-mesh sieve is providedbetween the container and the pump is particularly advantageous. Thepositioning of this fine-mesh sieve in the outlet opening of thecontainer is preferred.

The level sensor is designed in such a way that it can differentiatebetween different filling levels, this can be used very effectively toindicate readiness for use when the filling level is normal, and togenerate a refill signal when a predetermined lower filling level isreached. In one particularly advantageous embodiment, the metering unitis automatically switched off when a minimum filling level is reached toavoid errors and possible damage to or destruction of the metering pumpthis way. In a preferred embodiment, the level sensor is a float switch.

In another particularly advantageous embodiment provided by integrationof the metering unit, a piston diaphragm pump is used as the meteringpump. This provides for the stepless control of metering integrated in asimple and favorable manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned advantages and other advantages are illustrated bythe following description of one example of an embodiment of theinvention in which like items are identified by the same referencedesignation, shown in the accompanying drawings, in which like items areidentified by the same reference designation, wherein:

FIG. 1 is a sectional side elevational view, of the metering unit of theinvention; and

FIG. 2 is a side elevational view of the metering unit turned through90°.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the container 2 having a filling opening 3—located in theupper part—that is designed to be closed by a cover 4. Located in theconically tapering base is the outlet opening 5 in which a fine-meshsieve 12 is disposed, and above which is provided a refill bag formed bycrossed blades.

Arranged beneath the outlet opening 5 is a chamber 8 in the loweropening of which a connecting line 18 carrying the product to be meteredto the integrated metering pump 7 is present. The metering pump 7 may beformed, for example, by a piston diaphragm pump from which a productline 10 leads to the user situated outside the unit. In the illustratedembodiment, the user could be, for example, an institutional dishwashingmachine to which a rinse aid is thus fed in the necessary quantities asand when required. In addition, a return line 11 leads from the meteringpump 7 to a return opening in the side wall of the container 2.

Arranged in the chamber 8 is a level sensor 9 provided by a floatswitch. The float switch enables a ready signal to be generated when thefilling level is normal and a refill signal to be generated when thefilling level is low. These signals may be formed by acoustic signalgenerators 13 or optical signal generators 14 (see FIG. 2). The meteredvolume can be steplessly controlled by a control knob 15 on the meteringpump 7, as shown in FIG. 2.

If the metering unit 1 needs to be refilled, the cover 4 is removed anda refill bag is introduced through the opening 3 and slit open by thecrossed blades 6. The weight of the refill bag itself is sufficient forthe bag to be slit open when it comes into contact with the opener 6.The illustrated arrangement of crossed blades 6 opens the bag at itsbase in such a way that complete opening of the refill bag isguaranteed. The bag is withdrawn in such a way that the every last dropof the refill liquid can be removed, optionally after a holding phase.

The interior of the container 2 communicates directly with the chamber 8arranged beneath the container 2 so that the liquid poured in reachesthe bottom of the chamber 8. If impurities are introduced into the unit1 with the refill bag (not shown) or if parts of the refill bag becomedetached during opening, the fine-mesh sieve 12 disposed in the outletopening 5 in the illustrated embodiment prevents thoseimpurities/fragments from entering the chamber 8 where they could causeblockages in passages and lines or could interfere with the float switch9. In particular, the fine-mesh sieve 12 prevents impurities or foreignbodies from functionally impairing the pump.

If, as in the illustrated embodiment, the metering pump 7 is formed by apiston diaphragm pump, the metered volume can be steplessly controlledvery easily. The volume of liquid delivered per diaphragm stroke whichexceeds the set volume is guided to the return line 11 through a secondoutlet opening. The return line 11 is connected to an opening in theside wall of the container through which the volume returned is directlybrought back into the storage container 2.

Space for accommodating the electrical and electronic controls isavailable in the lower part of the metering unit 1 on the side oppositethe pump space. In this way, the mechanisms and devices for carrying outthe various functions of the integrated metering unit can beaccommodated in a very small space in a compact, but neat and readilyaccessible manner.

Although an illustrated embodiment of the invention has been shown anddescribed, it is not meant to be limiting. Those of skill in the art mayrecognize various modifications to this embodiment, which modificationsare meant to be covered by the spirit and scope of the appended claims.

What is claimed is:
 1. A metering unit comprising a storage containerwhich, in an upper part, has an opening for the introduction of refillbags holding a liquid and, in a base portion, comprises an outletopening above which a device for opening the refill bag is disposed,said unit further including a pump, and a chamber located below theoutlet, wherein the container and the chamber are made liquid-tight tohold the liquid without a refill bag, the chamber further including alevel sensor adapted for sensing filling levels, respectively, of theliquid held therein, and the pump is a metering pump integrated in ametering unit of which the inlet is connected to the chamber, and fromwhich a metering line leads to a user outside the metering unit, and areturn line leads back to the storage container.
 2. A metering unit asclaimed in claim 1, wherein the metering unit is automatically switchedoff when the filling level is minimal.
 3. A metering unit as claimed inclaim 1, wherein the level sensor is a float switch.
 4. A metering unitas claimed in claim 1, wherein the metering pump is a piston diaphragmpump.
 5. A metering unit as claimed in claim 4, wherein the pistondiaphragm pump includes a control knob for the stepless control ofmetering.
 6. A metering unit as claimed in claim 1, further including afine-mesh sieve arranged between the container and the pump.
 7. Ametering unit as claimed in claim 6, wherein the metering unit isautomatically switched off when the filling level is minimal.
 8. Ametering unit as claimed in claim 6, wherein the level sensor is a floatswitch.
 9. A metering unit as claimed in claim 6, wherein the meteringpump is a piston diaphragm pump.
 10. A metering unit as claimed in claim6, wherein the fine-mesh sieve is disposed in said outlet opening.
 11. Ametering unit as claimed in claim 10, wherein ready and refill signalsare generated at normal and low filling levels, respectively.
 12. Ametering unit as claimed in claim 10, wherein the metering unit isautomatically switched off when the filling level is minimal.
 13. Ametering unit as claimed in claim 10, wherein the level sensor is afloat switch.
 14. A metering unit as claimed in claim 10, wherein themetering pump is a piston diaphragm pump.
 15. A metering unit as claimedin claim 6, wherein ready and refill signals are generated at normal andlow filling levels, respectively.
 16. A metering unit as claimed inclaim 15, wherein the metering unit is automatically switched off whenthe filling level is minimal.
 17. A metering unit as claimed in claim15, wherein the level sensor is a float switch.
 18. A metering unit asclaimed in claim 15, wherein the metering pump is a piston diaphragmpump.
 19. A metering unit as claimed in claim 15, wherein the signalsare generated by optical signal generators and/or acoustic signalgenerators.
 20. A metering unit as claimed in claim 19, wherein themetering unit is automatically switched off when the filling level isminimal.